I’m writing to you from my husband’s hospital room. He had a total hip replacement two days ago. The nurse says he can go home as soon as the lab values come back with acceptable hemoglobin levels. What does this tell them?

Hemoglobin helps transport oxygen into the cells and carbon dioxide out. It is also a measure of how many red blood cells are in the blood. Normal hemoglobin ranges from 12 to 15 g/dL in women and 14 to 16.5 g/dL in men. Patients are followed more closely when levels drop below 10. The patient is very tired and may need a blood transfusion when levels drop below 8 d/dL.

Hemoglobin levels before an operation can help predict who might need a blood transfusion after surgery. Patients with low hemoglobin levels are at greater risk than patients with normal hemoglobin levels. Of course, a blood transfusion depends on how much (if any) blood was lost during the procedure.

Blood loss and transfusion usually means a longer stay in the hospital. On the other hand patients with good hemoglobin levels before coming into the hospital are more likely to go home sooner after surgery.